The problems associated with the disposal of such supplies are discussed in an article by Steven A. Weinstein and edited by Sue Crow, published in Infection Control, Volume 6, No. 1, 1985. This article sets out a number of desirable features of containers intended for this purpose, and which are believed to represent current thinking in the field. As far as the requirements set forth for the opening into the container are concerned, it should be emphasized that it is now considered important on the one hand that the opening into the container be easy to use and encourages safe handling of supplies by busy medical personnel, but on the other hand that it presents a substantial resistance to attempts to remove material from the container and that it avoids the presence of contaminated areas on the exterior of the container. These requirements are quite difficult to reconcile, particularly bearing in mind that it is difficult to provide an opening large enough to pass readily a 60 cc disposable syringe, which may be up to 25 cm long if the plunger is extended and may have a width over the finger grips of some 5 cm, whilst preventing hand access to the interior of the container. This problem is aggravated where a relatively compact container is required, as for bedside use (where prevention of patient access is very important), or use on mobile trolleys.
Examples of containers intended for use in receiving expended medical supplies of the type discussed above are to be found in U.S. Pat. No. 3,226,007 issued to Thies et al on Dec. 28, 1965; U.S. Pat. No. 4,121,755 issued to Meseke et al on Oct. 24, 1978; U.S. Pat. No. 4,315,592 issued to Smith on Feb. 16, 1982; and U.S. Pat. No. 4,488,643 issued to Pepper on Dec. 18, 1984. All but the Pepper patent contemplate the use of corrugated cardboard or similar foldable material to provide a container which is cheap to produce and can be knocked down for storage, and all provide some form of restriction of the container opening.
The Thies container provides an arrangement of interacting flaps in the top of the container which form a valve through which syringes may be pushed longitudinally into the interior of the container, and which prevents egress of an item once inserted. Although longitudinal insertion through a multi-flap valve enables the size of the valve opening to be minimized, it falls short of current desiderata in certain respects. Firstly, a user may need to use fingers to push an item right through the valve, and in doing so risks needle stick if the contents reach near the top; a tamperer also faces similar risks. Secondly, the endwise pushing of the syringe produces two problems. If the syringe is inserted needle first, as will normally be the case, the bottom of the container must be able to resist the direct impact of the needle, and residual fluid may be ejected from the syringe on impact. If the syringe is reversed for any reason, the user again risks needle stick. The exterior flap covering the opening is moreover likely to become contaminated during use of the container.
The Meseke container improves upon the Thies container in two respects, in that it permits sideways insertion of syringes and may provide an outer flap to cover the contaminated flap areas prior to removing the container for disposal. The increased size of the valve however means that there is little restriction on hand entry through the flap valve, even though such entry is less necessary during normal usage.
The Smith patent recognizes the importance of allowing materials to be placed in the container without a user risking injury from its existing contents. It thus provides the container with an outer lid containing a first longitudinal opening through which a syringe or similar article may be dropped sideways on, and an internal flap structure defining a ramp beneath the first opening which directs the article through a second longitudinal opening laterally displaced from the first opening, into the interior of the container proper. When the container is to be removed for disposal, the internal flap may be pulled outwardly through a slot so as to pull the ramp upwardly to close the opening in the upper lid. Although the labyrinth provided by the laterally offset outer and inner openings makes hand access more difficult, dimensional limitations make it difficult to provide adequate security in a compact container, and the fact that the edges of the openings are unsupported and cut through a single thickness of cardboard means that it is possible for somebody to force their hand through the openings without too much difficulty. It is also difficult to design the openings so as to allow easy passage of articles without unduly weakening the structure, and the container after use presents external surfaces which may be contaminated.
The Pepper structure provides somewhat similar functionality to the Thies container, but in moulded synthetic plastic and with the addition of a needle bending or breaking device. At one time, it was considered desirable, and in some jurisdictions required, to bend or break the needles of syringes prior to disposal, in order to prevent subsequent misuse. Current thinking is that such bending or breaking during or prior to insertion of a syringe into a disposal container is undesirable, both because of the risk of needle stick injuries, and because of dispersion of fluid material in spray or aerosol form which can take place at the instant of breakage.